Powered thread cutter



July 21,1970 s. H. 'BAKYER I 3,

POWER-ED THREAD CUTTER. Filed Dec. 13, 19 67 2 sheets sh'eet 2 INVENTOR. 62425 A? EAKEZ United States Patent O1 lice 3,521,313 Patented July 21, 1970 US. Cl. 1089 5 Claims ABSTRACT OF THE DISCLOSURE A thread cutter having a ring gear and interconnected 7 die holder concentrically mounted for rotational movement within an outer casing is provided with a worm gear rotatably mounted for driving engagement with said ring gear, and with outwardly extending handles located on opposite sides of the casing. A coupling device on both ends of the worm gear drive shaft permits the worm gear, and the ring gear and die holder driven thereby, to be rotated in opposite directions by connecting a rotating power source to either end of the worm gear drive shaft. The gear drive arrangement and the casing handles serve as alternative means for turning the thread cutter on a pipe or rod on which threads are to be formed.

This invention relates to thread cutters of the type incorporating thread cutting dies mounted within a frame or casing for rotational movement about a pipe or rod to be threaded. The primary objective of this invention is to provide such a thread cutting device which is capable of either manual or power-driven operation, and which is provided with means for reversing the direction of rotation of the thread cutting dies.

In the preferred form of my invention, the power drive arrangement is comprised of a ring gear rotatably mounted within an outer casing and a worm gear mounted in one end of the casing for driving engagement with the ring gear. A removable die holder is concentrically supported within the ring gear for rotational movement therewith, thereby providing a very compact thread cutting mechanism.

A particularly advantageous feature of my invention resides in the utilization of handles extending from opposite sides of the casing as a means for manually actuating the thread cutting dies and for restraining the die casing against rotational movement when the thread cutters are being driven by an external power source connected to the worm gear.

The utility and versatility of my thread cutting apparatus is further improved by providing coupling means on the opposite ends of the worm gear drive shaft so'as to permit the worm gear, and the ring gear and die holder driven thereby, to be rotated in opposite directions by a rotating power source.

These and other objects and advantages of my invention will become readily apparent as the following description is read in conjunction with the accompanying drawings, of which:

FIG. 1 is a front elevation view, partially in section, of my improved thread cutter;

FIG. '2 is a top view of the thread cutter with a portion of the outer casing broken away; and

FIG. 3 is an exploded, perspective view of the thread cutter of this invention. 1

The thread cutter of this invention has been particularly designed with a view towards providing a device for cutting threads on a pipe or rod which can be powerdriven or operated manually, and the direction of rotation of which can quickly and easily be reversed regardless of whether the rotary power source is reversible. These advantageous features have been incorporated in a thread cutter having parts uniquely constructed so as to provide an unusually compact and easily serviceable device. The preferred embodiment of myinvention as illustrated in FIGS.,1 and 2 is comprised of an outer casing 1 of generally cylindrical shape and a die holder 2 rotatably supported therein. A plurality of thread cutting dies 4 extend radially inwardly'from the inner periphery of annular die holder 2, and in the embodiment illustrated are shown as being integral with the die holder. A die holder having thread cutting dies removably inserted therein could also be utilized. In order to rotatedie holder 2 so as to cut threads on a work piece such as rod or pipe 6, I have provided both manual turning and power drive arrangements.

Die head or holder 2 is driven by ring gear 8 within which die holder 2 is concentrically mounted for driving engagement by means of an arrangement of lugs 10 and grooves 12. Lugs 10 around the inner periphery of ring gear 8 fit within mating grooves 12 when die holder 2 is slidably inserted within the ring gear. The assembly of ring gear 8 and die holder 2 is positioned within outer casing 1 for rotation as a single unit.

This arrangement of parts and the manner in which they are installed in casing 1 can most easily be understood by reference to FIG. 3 as well as to FIGS. 1 and 2. Shoulders 14 on the opposite sides of ring gear 8 are rotatably supported in milled races 16 machined into the inner walls 18 of casing 1. Shoulder portions 20 of die holder 2 project axially beyond both sides of ring gear -8 and bear against top and bottom covers 22 and 24 respectively of casing 1. Recessed walls 26 of outer casing .1 serve as hearing surfaces which contain and rotatably support outer shoulder portions 20 of die holder 2. Top cover 22 is removably secured to casing 1 by means of thumb screws 28. Cover plate 22 may easily be removed by simply loosening thumb screws 28, rotating plate 22 so that enlarged holes 32 in slots 30 are in line with thumb screws 28, and then lifting plate 22 over the heads of the thumb screws. Die holder 2 can then be removed by simply turning casing 1 upside down from the position shown in FIG. 1. Die holder 2 will fall out and a new die holder having different size thread cutters may be installed in order to accommodate rods or pipes of different diameters. By mounting die holder 2 concentrically within ring gear 8 and utilizing a die holder of the type shown with radially disposed thread cutting dies 4 which lie in the same plane as ring gear 8, the assembled thread cutting unit is quite compact and of minimal width. Top cover 22 has a central opening 34 aligned with opening 36 in fixed bottom panel 24 through which rod or pipe 6 extends. v

For the purpose of driving ring gear 8 by an external power source, a drive gear in the form of worm gear 38 is housed within enlarged portion 40 of casing 1. Gear housing '40 is of circular'cross section and is provided with openings at each end through which worm'gear drive shaft 42 extends. Each of the opposite ends 44 and 46 of worm gear drive shaft 42 are of square cross section so as to permit them to be coupled to a com plementary socket 48 having a stub shaft 50 which can be fastened in the chuck 52 of an ordinary, portable hand power drill 54. Worm gear drive shaft 42 is journaled at its opposite ends in tapered roller bearings 56 and 58. The end thrust generated by worm gear 38 is absorbed by one set of roller bearings 56 or 58 depending upon the direction in which worm gear 38 is being rotated. Worm gear 38 is arranged so that its gear teeth mesh with and drivingly engage the teeth or ring gear 8.

In order to permit my thread cutter to be operated manually as well as by an external power source, I have provided outwardly projecting handles 60 and 62 which extend along a common line from opposite sides of casing 1. It is to be noted at this point, that worm gear drive shaft 42 extends axially of worm gear 38 in a direction substantially perpendicular to handles 60 and 62. This arrangement of worm gear drive shaft 42 with respect to handles 60 and 62 permits an operator to hold hand drill 54 on drive stub 44 or 46 with one hand and grasp oppositely disposed handle 62 with the other hand. With hand drill 54 coupled to drive stub 46 in the manner indicated in FIG. 2, worm gear 38 will rotate in the direction indicated by the arrow in FIG. 1 and ring gear 8 and die holder 2 will rotate in the clockwise direction shown by the arrow in FIG. 2. The operator may thus hold drill 54 in his left hand and utilize his right hand to grasp handle 62 so as to counter the torsional force imposed on casing 1 by the rotation of ring gear 8. Worm gear drive shaft 42 has been disposed at an angle of substantially 90 with respect to handles 60 and 62 as this arrangement makes it most convenient for the operator to grasp handle 62 with one hand when he is holding power source or drill 54 in the other hand. The torsion-countering advantage could still be achieved, but possibly with slightly less convenience, so long as one of the handles is located across casing 1 from worm gear 38 and disposed at an angle with respect to worm gear drive shaft 42.

In operation, a work piece in the form of a rod or pipe 6 will be secured in a vise at one end with the opposite end to be threaded extending through axially aligned holes 34 and 36 in casing 1 in the manner indicated in FIGS. 1 and 2. If no source of power is available, or if it is desired to make the initial thread cut manually, casing 1 and die holder 2 firmly secured therein may be rotated on pipe 6 by exerting turnin leverage on handles 60 and 62. For power actuation, it is only necessary to slip drive socket 48 of a motor driven hand drill over stub end 46 of drive shaft 42 and turn on the drill. The rotation of worm gear 38 in the direction indicated by the arrow in FIG. 1 will impart a clockwise rotary motion to ring gear 8 and attached die holder 2 causing the entire thread cutting device to run down on pipe 6 as threads 7 are cut thereon. If the power drill or other power source is not reversible, it may be detached from stub end 46 and coupled to oppositely disposed stub end 44 in order to reverse the direction of rotation of die holder 2 and back it off of pipe 6. The attachment of the rotating power source to stub end 44 may conveniently be accomplished by merely revolving the entire thread cutting assembly one half turn on pipe 6 in order to bring stub end 44 around to a position facing the operator.

By providing handles 60 and 62 in combination with the above-described gear drive arrangement, I have developed a thread cutter which is versatile and which lends itself to particularly easy manipulation and operation. It is contemplated that various changes and modifications may be made to my thread cutting device without departing from the spirit and scope of my invention as defined by the following claims.

What is claimed is:

1. A thread cutter comprising in combination:

an outer casing having a drive gear rotatably mounted on one side thereof;

gear means mounted for engagement with said driven gear, said gear means being connected to a rotatably supported, thread cutting die holder, said outer casing and said die holder having axially aligned openings therein through which a pipe to be threaded extends;

a drive shaft connected to said drive gear and having outwardly extending, opposed end portions, both of said drive shaft end portions having permanently accessible and exposed coupling members thereon, constructed and arranged to permit ready and quick detachable coupling thereof to the chuck of a portable electric drill, whereby said drive gear, and said gear means and die holder driven thereby, may be rotated in opposite directions by coupling said portable electric drill to either of said drive shaft end portions.

2. A thread cutter as defined in claim 1, and further including:

two outwardly projecting, elongated handle bars extending from opposite sides of said outer casing, said handle bars being of sufficient length to provide the necessary torque leverage for turning said thread cutter manually, and at least one of said handles being located directly across said casing from said drive shaft and extending at an angle with respect thereto, whereby the rotational force imparted to said casing by the rotating action of said die holder may be countered by grasping said one of said handles.

3. A thread cutter as defined in claim 2, wherein:

said drive gear is in the form of a worm gear;

said gear means comprises a ring gear; and

said drive shaft extends along a line substantially normal to said outwardly projecting handles.

4. A power driven thread cutter comprising:

an outer casing including oppositely disposed cover portions, at least one of which is removable;

a drive gear rotatably mounted on one side of said casing;

a drive shaft connected to said drive gear, and having at least one end thereof constructed and arranged for connection to an external, rotating power source;

a driven, ring gear rotatably supported within said casing;

a die holder mounted within said ring gear and connected thereto for rotational movement therewith, said die holder having opposed shoulder portions projecting axially beyond both sides of said ring gear, said casing having recessed portions on the opposite sides thereof adjacent said oppositely disposed cover portions which serve as bearing surfaces for said die holder shoulder portions, said casing, die holder and oppositely disposed cover portions having axially aligned openings therein through which a pipe to be threaded extends; and

a plurality of thread cutting dies extending radially inwardly from said die holder, said thread cutting dies being coplanar with said ring gear.

5. A thread cutter as defined in claim 1 wherein:

said gear means comprises a ring gear rotatably supported within said casing, and said die holder is mounted concentrically within said ring gear, said die holder having shoulder portions projecting axially beyond both sides of said ring gear, and said outer casing being provided with recessed portions on the opposite sides thereof which serve as bearing surfaces for said die holder shoulder portions; and

a plurality of thread cutting dies extending radially inwardly from said die holder, said cutting dies being coplanar with said ring gear and contained therein to thereby provide a compact thread cutter assembly of minimum width and weight.

References Cited UNITED STATES PATENTS 1,789,411 1/1931 Oster et al. 1089 1,852,776 4/ 1932 Hodeaux 10-89 2,205,148 6/ 1940 Mayotte 10 89 2,678,453 5/1954 Rudolph 10-89 3,316,571 5/1967 Cutrone 10-89 CHARLES W. LANHAM, Primary Examiner E. M. COMBS, Assistant Examiner 

